Alkylation of hydrocarbons



Aug. 12, 1947. L. u. FRANKLIN Y 2,425,452

` LKYLATIQN OF HYDROCARBONS Filed Maron 28,1946

OLIE/FIN ISOPBRHFFIN Las/le U. Frank/ln 6% 3441s @www Patented Aug. 12, 1947` Urll'riau"v f srA'rss APl/riuscii orslcs f Leslie U. Franklin, Port Arthur, Tex., assignor to Gulf Oil Corporation, Pittsburgh, Pa., a corv poration of Pennsylvania Application March 28, 1946, Serial No. 657,834

3 Claims. (Cl. 260--683.4)

This invention relates to alkylation of hydrocarbons, and more particularly it relates to alkylation' of hydrocarbons with the aid of anhydrous aluminum chloride as catalyst.

The' alkylation of olen hydrocarbons with isoparaffins is now a Well established art and many proposals have been made for accomplishing it with the aid of anhydrous aluminum chloride. However, this material has many characteristics which limit its use as a catalyst 'or make its use prohibitlvely expensive. The use of aluminum chloride as a catalyst for hydrocarbon reactions generally has been restrictedbecause of its reactivity. but this reactivity is not necessarily objectionablein the case of alkylation because the reaction product of anhydrous aluminum chloride and hydrocarbons-particularly oleiins-is itself a very good catalyst for such alkylation.

The reaction product of anhydrous aluminum chloride and light hydrocarbons may vary greatly in physical properties. It may be a moderately v viscous liquid or lit may be a. relatively hard solid,

and the particular "physical properties of this reaction product Will control the adaptability of the material as a catalyst :for alkylation. Highly uid catalysts call for the use of much power for agitation of the catalyst and hydrocarbons to obtain the necessary contact of lreactant hydrocarbons lwith the catalysts. Theless uid catalysts pos'e a substantially insuperable'problem in trying to get adequate contact surface of catalyst to hydrocarbons. The catalyst in this case is much too thick to permit of its being stirred Iwith the hydrocarbons in order to present extensive contact surface, while all efforts to use such material in the form of discrete particles is defeated because the particles will slough together into a cohesive mass.

Anhydrous aluminum chloride itself is a reasonably hard solid, and discrete pieces of the -`'of a plastic aluminum chloride reaction product, and by which I am enabled to maintain a hard and permeable catalyst bed throughout the lire l of the catalyst.

I have discovered that if the alkylation is conducted at a temperature Within'the approximate range of 50 F. to 75 F. with a contact time in the catalystbed of from about one second to vabout ten seconds, while maintaining the olefin rcontent in the feed stream within the approximate range of 0.1 per cent to 2.5 per cent, I can effect alkylation ata very satisfactory rate and Vmaintain the catalyst bed firm and porous.

Temperatures in the lower-part of the preferred range will permit a.- slight increase in the minimum reaction time and will also produce an l alkylate containing a slightly higher proportion of primary reaction products. Temperatures in the higher-portion of ,the preferred range tend to produce more rearranged or secondary reaction products, and-this tendency is more pronounced when butenes'and pentenes are the olensused than when ethene or propene are the olefin used. The time of contact between the hydrocarbons undergoing alkylation and the alkylation catalyst should be between one second andtenseconds. The preciseintefrval may `well vary inversely with the `olefin concentration and the temperature. For example, when alkylating material may be built up into a porous bed. Efy forts have been made to use such a bed of anhydrous aluminum chloride asa catalyst material but the invariable experience has been that veryy butenes with isobutane at a temperature of 75 F. *with anolefin content `of 2.5 per cent. the` maximum reaction time may advantageously be about one second,l while this reaction time may be extended to about ve seconds vwhen the olefin `content is reduced to about 0.5 per cent. 'I'he` contact time of one to tenv seconds herein speciiied is based on the fresh charge tothe system, exclusive of any recycle, and may be defined as the ratio of the volume of voids in the catalyst bed to the volume of such fresh charge introf duced into the system per second of time.

I shall nowl further describe my process in connection with the attached drawing.

The equipment'required for practice of my in vention is of conventional design, as here described, and it is operated as follows: An olefin or olefin-containing stock is introduced through line I to the suction side of a pump 3. Suitable stock for this olefin feed may be ethene,'propene,

butenes, pentenes, or mixturesvoff some of these. -An isoparaffln or anl isoparaflln-containing stream is introduced through line 2 to the suctionvside of pump 4. Suitable isoparafilns comprise isobutane or isopentane or a mixturegthereof. The olefin stream leaving pump 3 through line and the isoparafiln stream leaving pump 4 .through line 8 :loinn in line ,'I andare conducted Y Fractionator I8 is oi vconventional bubble-tray or packed design and may be equipped with suitkable .redux 'and .temperature and pressure cont trol. meansnot shown,.andit may also'be equipped a bed o1' catalyst 2|, this bed being initially built up of discrete particles of anhydrous aluminumY chloride. In .order to reduce the weight .onthe lowermost particles, the catalyst may be divided between two'or more grills `2I'I placedA oneabove another in reactor 8. The particle size of the aluminum chloride catalyst may vary from a rela tively fine granular` material up to lumps approxi-'- mating an inch in diameter, vor even more, de-

pending principally upon the size of the chamber, the reaction time and the space velocity desired, The hydrocarbon feed line 'I enters the base of reactor 8 at a point below the catalyst bed, and the line 'I may terminate inside of reactor 8 with some kind of a distributing head-.if desired. Y

The mixture of isoparaiiins and olens lin its passage upward through the bed of aluminum chloride undergoes an alkylation reaction, thereby producing higher molecular vweight isoparaffins. Reaction chamber 8 is constructed with a height greater than that required forthe catalyst bed in order that there maybe some height of open chamber above the catalyst. "This is to permit-settling out of fine particles and thereby avoid their carrying over to subsequent portions of the apparatus. The rate of ilow of hydrocarbon through the reactor 8 is regulated s at the contact .time between the hydroc catalyst is held within the speci imit ofirom one to tenseconds, being go uminum chloride bed and the rater of intrluction of hydrocarbons.

'ghe-reaction productsv of' the alkylation step Y together with any unreacted materials ow out ofV the top of the-'reaction chamber 8 through line 9. VThe stream leaving chamber 8 through line.

9 will contain an appreciable quantity ofithe isoparans introduced through line 1 due to the fact that the content vof oleiins in line 1 is held to within 'a range of 0.1 per cent to 2.5,per cent Vand the additional fact v.that this proportion of olens is far below that required for reaction with the large proportion of isoparatiins present. As Lthe amount of. alkylate present in line 9 is low in proportion to the percentage of unreacted isoparans, it is -ordinarily advantageous to recycle much of this material through line I8 and pump II and line I2 back into feed `line 1. 1 Either all or a portion .of the contents of line 9 are conducted away through line I9 to a fractionating tower I3. Tower `I3 is of conventional bubble-trayor packed design. and may be equipped with suitable reflux; temperature and pressure control means, not shown. Fractionating Ltower I3 'is used 'to remove unreacted isoparan feed from .the alkylate, and

vthis unreacted isobutane or isopentane. goes overhead and is removedthrough line I4. Allor a portion of this stream maybe recycled through -n and with one or more side stream take-oils if desired.

VPrimary alkylateoi the desired boiling range and end point is removed overhead through line I1,

and heavy alkylate comprising relatively khighA 't 1 'boilingmaterial is removed'as a bottom product through line I8, A

Theeiiicacy of this process andthe new results obtained by it are well shown vby the following specific examples. Y

ned by the volume Y Example .e I II III With With Without Recycle Recycle Recycle oi Prodof Prodof Product uct uct Catalyst at Equilibrium Solid Y AlCla A1013 A101: Hydrocarbon Feed Mixture Com- Y position, Vol. per cent:

Propone 0. 03 0. 03 0. Propane 0. 20 0. 20 0. Isobutene. 0.01 A 0.01 0. Isobutane. 75. 00 475. 00 97. Butene-l 0. 06` 0.06 0. Butene-2 0.36 0.35 Y 0. Normal Butane 5.25 5. 50 1l. Recycle Alkylate f 19.09 18. 85

Total .100.00 100.00 160.00

Total Olens 0.46 0.45 k0.53 i

Ope-ating Conditions: Reaction Zone .Y

i Temperature, 60 60 60 Pressure, P. s. im..- 100 100 100 Reaction Time, Second 96' 5 Ratio, Gms. of A101; per Cc. of

Glenna/Blah` 1 17 1 3 Debutanized Rerun Product: Y

Yieldl y Vol. per cent of Olefln v 150 150 153 Vol. per cent of .Debut. Product 72 88 90 Inspection:

Octane No., CFR-AST Motor Method 80 92 Distillation, ASTM- Initial B. P., F 150 140 150 10% at' F l188 185 190 at F. '206 207 205 90% at; I238 234 229 Final B. P., F 260 257 V241- lApprox.

l An 4examination of the abovespeciflc examples will show'many distinctions from the prior 1 art', and it willparticularlydlsclose that the iivef'sec'- ond reaction time usedin'Examples It and III,

\ resulted in 88 percent and 90 per cent yields of (92 and Vl94 octane alkylates, as compared with a 72 per cent yield of only 80 octane product Vwhen line 2 for introduction-into vessel 8 by means not shown. In addition to the isoparafiin, this stream of fractionator I3 ythrough line I5 and is `then.

conducted to' fractionator I6 for final separation into two or more streamsof desired boiling range.

operating with -the 96 seconds reaction time :of Example I. All conditions other. than reaction time are maintained substantially alike in-,thev

.various examples. y

. Recycling of ka Aportion of a portion ofL the reactor eiliuenteifects av high dispersion of olen in the charge stock and is equivalent to providing the reactorwith an internal stirring mechanism or an internal circulation system, neither-of which is practical withfa stationary catalyst bed. The recycling vresults in a high internal ratio'of isoparaftin toolefin'and minimizes olen concentration at anyone point within the reactorsystem. Such a procedureV would Yordinarily be y adoptedin rcommercial.operation andvwas used in the operations reported in specicExamples I andII above.

An important advantage of myy process is thatv it produces a greater proportion of primary alkylationproducts than is produced by `the processes of the prior art. By primary alkylation` product I mean the alkylation products which are first formed directly from the original hydrocarbons charged, without extensive subsequent re-arrangement to other compounds.

The primary advantage of my process, as already pointed out, is that it permits the economical use of anhydrous aluminum chloride as acatalyst in the alkylation of hydrocarbons, this being so because it shows the way, for the iirst time in this art, to indefinitely maintain a per-,f meable bed of hard discrete particles of anhydrous aluminum chloride catalyst, even after the aluminum chloride has undergone reaction with hydrocarbons.

When aluminum chloride is used as a catalyst it is frequently mounted on unreactive carrier materials such as carbon, diatomaceous earth, silica, alumina, magnesia, magnesite, crushed iire brick, aluminum silicates, porcelain, clays, fullers earth,l bentonite, montmorillonite, etc. and other refractory porous substances which have substantially no reactivity with anhydrous aluminum chloride. In the appended claims, when I speak of a catalyst bed made up of discrete particles of anhydrous aluminum chloride unmounted on any unreactive carrier I mean thereby discrete particles of anhydrous aluminum chloride not mounted upon and substantially free of unreactive carrier materials such as those named in this paragraph.

What I claim is:

l. In the alkylation of an olen with an lsoparain the process which comprises passing a mixture of hydrocarbons comprising oleiins and isoparains through a catalyst bed made up of discrete particles of anhydrous aluminum chloride unmounted on any unreactive carrier, maintaining the proportion of olens in the hydrocarbon feed stock within the approximate range of 0.1 per cent to 2.5 per cent, maintaining the time of contact of hydrocarbon and aluminum chloride within the range of from one second to ten seconds, and maintaining the temperature within the approximate range of 50 to 75 F.

2. In the alkylationof hydrocarbons with the 6 aid of anhydrous aluminum chloride, the process of maintaining a permeable bed made up of anhydrous aluminum chloride catalyst which comprises setting up a permeable bed of discrete particles of anhydrous-aluminum chloride unmounted onany unreactive carrier, passing'a stream of isoparanin and olefin hydrocarbons to be alkylated through the bed of aluminum chloride at a temperature within the approximate range of to 75 F. at such a rate` of now that the time of contact of hydrocarbonwith catalyst will be not less than one second or more than ten seconds, and maintaining the olen contentvof the said hydrocarbon stream being introduced into said permeable bed of anhydrous aluminum chloride within the approximate range of 0.1 per cent to 2.5 per cent.

3. The process of alkylating hydrocarbons which comprises passing a mixture of hydrocarbons comprising olens and isoparamns through a catalyst bed 4made up of discrete particles of anhydrous aluminum chloride unmounted on any unreactive carrier, maintaining the content or olens inthe hydrocarbon feed stock within the approximate range of 0.1 per cent to 2.5 per cent,

maintaining the ow of hydrocarbons over the catalyst at such a rate that the time of contact of hydrocarbon with catalyst will be not less than one second and not more than ten seconds, and maintaining the temperature of the hydrocarlignsp within the approximate range oi 50 to `I FEZSLlJEI U. FRANKLIN.

REFERENCES 'CITED The following references are of' record in the file of this patent:

UNITED. STATES PATENTS Number Name Date 2,394,368 Clarke Feb. 5, 1946 2,332,564 Egloi Oct. 26, 1943 2,318,781 Ipatieff et al May 11, 1943 2,298,383 Ipatiei et al. Oct. 13, 1942 

